Pricing Model Comparison

Interchange-Plus vs Flat-Rate Credit Card Processing

Compare interchange-plus and flat-rate card processing with transparent formulas, break-even examples, and small-business decision criteria.

Flat-rate processing charges one blended price, such as 2.6% + $0.15 for in-person payments. Interchange-plus passes through the card's actual interchange and network costs, then adds a processor markup, such as 0.40% + $0.08. Flat-rate is easier to predict. Interchange-plus can cost less for the right volume and card mix, but the published markup is not the total rate.

Interchange-Plus vs Flat-Rate at a Glance

Question	Interchange-plus	Flat-rate
How the price works	Actual interchange and network costs pass through, then the processor adds a disclosed percentage and transaction markup.	The processor charges one blended rate for a payment channel, regardless of the underlying eligible card cost.
Predictability	Monthly cost changes with card type, channel, ticket size, and qualification.	Easy to estimate when the published rate and payment channel are known.
Statement transparency	Can show wholesale cost and processor markup separately, although statement layouts vary.	Simple statement, but the processor spread over underlying cost is not itemized per card.
Common fit	Growing merchants with enough volume to audit statements and benefit from lower-cost card mix.	Newer or lower-volume businesses that value fast setup and predictable pricing.
Main risk	Treating the advertised markup as the total rate or ignoring monthly and account fees.	Paying a larger blended spread as volume grows or using expensive card-not-present rates.

The Two Cost Formulas

Flat-rate monthly cost

sales x flat percentage + transactions x fixed transaction fee + monthly fees

Interchange-plus monthly cost

actual interchange and network costs + sales x processor markup + transactions x processor transaction markup + monthly fees

A quote that says only “interchange + 0.40% + $0.08” is incomplete until actual interchange, network assessments, account fees, and payment-channel mix are included.

Break-Even Examples Using Public Starter Rates

These examples compare Square Free's 2.6% + $0.15 in-person rate with Helcim's $0-$50K tier processor markup of 0.40% + $0.08. The final column is the maximum room left for wholesale interchange and network costs before the modeled interchange-plus total reaches the flat-rate total. It is not a predicted Helcim all-in rate.

Monthly sales	Average ticket	Transactions	Flat-rate total	Processor margin only	Wholesale break-even budget
$10,000	$50	200	$290	$56	$234, or 2.34%
$25,000	$50	500	$725	$140	$585, or 2.34%
$50,000	$75	about 667	about $1,400	about $253	about $1,147, or 2.29%

Compare Against Your Actual Effective Rate

Start with your statement, not a provider's lowest example. Enter total card sales, average ticket, current percentage, transaction fee, and fixed monthly fees, then compare the result with written quotes.

Run the fee calculator Compare Helcim vs Square

How Card Mix Changes the Answer

Under interchange-plus pricing, debit, basic consumer credit, rewards, commercial, international, and card-not-present transactions can carry different pass-through costs. A merchant with many lower-cost transactions may leave more room for savings than one with premium rewards and online cards.

Flat-rate pricing blends those differences into a predictable channel rate. That can simplify budgeting, but it also means the merchant does not directly benefit whenever underlying card cost is below the blended rate.

Quote Comparison Checklist

Calculate effective rate from at least two or three recent statements.
Separate card-present, online, keyed, invoice, and card-on-file volume.
Record average ticket and transaction count for each channel.
Ask whether the quote is true interchange-plus, flat-rate, tiered, or subscription pricing.
Get processor markup, monthly fees, PCI fees, gateway fees, minimums, and contract terms in writing.
Model the quote using your card mix instead of a provider's best-case example.
Compare annual total cost, hardware, software, payout speed, and workflow fit together.

Compare Current Pricing Models

Verify public rates, then request written pricing using the same monthly volume, ticket size, channel mix, and contract assumptions.

Helcim

Partner status pending

growing businesses
in-person merchants
lower-fee quotes

Visit official site

Square

Partner status pending

new businesses
restaurants
food trucks

Visit official site

Stripe

Official provider link

online payments
SaaS
developer-led businesses

Visit official site

Provider links may be official links or affiliate links. Pricing can change; verify current rates, monthly fees, hardware costs, and contract terms before signing up.

FAQ

Is interchange-plus always cheaper than flat-rate pricing?

No. Interchange-plus can be cheaper for some merchants, especially as volume grows, but the result depends on card mix, average ticket, processor markup, monthly fees, and payment channel. Flat-rate simplicity can still be valuable for a small or new business.

What does interchange plus 0.40% and 8 cents mean?

It means the processor adds 0.40% of sales plus $0.08 per transaction on top of the actual interchange and network costs. The 0.40% and $0.08 are not the complete processing rate.

At what volume should a business compare interchange-plus?

There is no universal threshold. A comparison becomes more worthwhile when processing is a meaningful monthly expense, often around $15,000-$30,000 or more in card volume, but card mix and ticket size can move the break-even point substantially.

How do I compare the two pricing models fairly?

Use the same monthly volume, transaction count, average ticket, channel mix, card mix, software, hardware, and account fees. Compare total monthly cost and effective rate rather than one advertised percentage.

Methodology and Limitations

Public Square, Helcim, Stripe, Visa, and Mastercard pages were checked on August 9, 2026. Break-even examples use only the stated flat rate and processor markup; they deliberately do not invent a universal interchange rate. Real wholesale costs vary by card, channel, merchant category, and transaction qualification.

This is an educational comparison, not a processor quote or financial advice. Confirm current pricing, account fees, contracts, and hardware on official provider pages before making a decision.

Source Notes

Pricing and methodology last verified: 2026-08-09.